C++ AliasSetTracker::getAliasAnalysis方法代码示例

void AliasSet::addPointer(AliasSetTracker &AST, PointerRec &Entry,
                          uint64_t Size, const MDNode *TBAAInfo,
                          bool KnownMustAlias) {
  assert(!Entry.hasAliasSet() && "Entry already in set!");

  // Check to see if we have to downgrade to _may_ alias.
  if (isMustAlias() && !KnownMustAlias)
    if (PointerRec *P = getSomePointer()) {
      AliasAnalysis &AA = AST.getAliasAnalysis();
      AliasAnalysis::AliasResult Result =
        AA.alias(AliasAnalysis::Location(P->getValue(), P->getSize(),
                                         P->getTBAAInfo()),
                 AliasAnalysis::Location(Entry.getValue(), Size, TBAAInfo));
      if (Result != AliasAnalysis::MustAlias)
        AliasTy = MayAlias;
      else                  // First entry of must alias must have maximum size!
        P->updateSizeAndTBAAInfo(Size, TBAAInfo);
      assert(Result != AliasAnalysis::NoAlias && "Cannot be part of must set!");
    }

  Entry.setAliasSet(this);
  Entry.updateSizeAndTBAAInfo(Size, TBAAInfo);

  // Add it to the end of the list...
  assert(*PtrListEnd == 0 && "End of list is not null?");
  *PtrListEnd = &Entry;
  PtrListEnd = Entry.setPrevInList(PtrListEnd);
  assert(*PtrListEnd == 0 && "End of list is not null?");
  addRef();               // Entry points to alias set.
}

/// mergeSetIn - Merge the specified alias set into this alias set.
///
void AliasSet::mergeSetIn(AliasSet &AS, AliasSetTracker &AST) {
  assert(!AS.Forward && "Alias set is already forwarding!");
  assert(!Forward && "This set is a forwarding set!!");

  bool WasMustAlias = (Alias == SetMustAlias);
  // Update the alias and access types of this set...
  Access |= AS.Access;
  Alias  |= AS.Alias;

  if (Alias == SetMustAlias) {
    // Check that these two merged sets really are must aliases.  Since both
    // used to be must-alias sets, we can just check any pointer from each set
    // for aliasing.
    AliasAnalysis &AA = AST.getAliasAnalysis();
    PointerRec *L = getSomePointer();
    PointerRec *R = AS.getSomePointer();

    // If the pointers are not a must-alias pair, this set becomes a may alias.
    if (AA.alias(MemoryLocation(L->getValue(), L->getSize(), L->getAAInfo()),
                 MemoryLocation(R->getValue(), R->getSize(), R->getAAInfo())) !=
        MustAlias)
      Alias = SetMayAlias;
  }

  if (Alias == SetMayAlias) {
    if (WasMustAlias)
      AST.TotalMayAliasSetSize += size();
    if (AS.Alias == SetMustAlias)
      AST.TotalMayAliasSetSize += AS.size();
  }

  bool ASHadUnknownInsts = !AS.UnknownInsts.empty();
  if (UnknownInsts.empty()) {            // Merge call sites...
    if (ASHadUnknownInsts) {
      std::swap(UnknownInsts, AS.UnknownInsts);
      addRef();
    }
  } else if (ASHadUnknownInsts) {
    UnknownInsts.insert(UnknownInsts.end(), AS.UnknownInsts.begin(), AS.UnknownInsts.end());
    AS.UnknownInsts.clear();
  }

  AS.Forward = this; // Forward across AS now...
  addRef();          // AS is now pointing to us...

  // Merge the list of constituent pointers...
  if (AS.PtrList) {
    SetSize += AS.size();
    AS.SetSize = 0;
    *PtrListEnd = AS.PtrList;
    AS.PtrList->setPrevInList(PtrListEnd);
    PtrListEnd = AS.PtrListEnd;

    AS.PtrList = nullptr;
    AS.PtrListEnd = &AS.PtrList;
    assert(*AS.PtrListEnd == nullptr && "End of list is not null?");
  }
  if (ASHadUnknownInsts)
    AS.dropRef(AST);
}

void AliasSet::addPointer(AliasSetTracker &AST, HashNodePair &Entry,
                          unsigned Size, bool KnownMustAlias) {
  assert(!Entry.second.hasAliasSet() && "Entry already in set!");

  // Check to see if we have to downgrade to _may_ alias.
  if (isMustAlias() && !KnownMustAlias)
    if (HashNodePair *P = getSomePointer()) {
      AliasAnalysis &AA = AST.getAliasAnalysis();
      AliasAnalysis::AliasResult Result =
        AA.alias(P->first, P->second.getSize(), Entry.first, Size);
      if (Result == AliasAnalysis::MayAlias)
        AliasTy = MayAlias;
      else                  // First entry of must alias must have maximum size!
        P->second.updateSize(Size);
      assert(Result != AliasAnalysis::NoAlias && "Cannot be part of must set!");
    }

  Entry.second.setAliasSet(this);
  Entry.second.updateSize(Size);

  // Add it to the end of the list...
  assert(*PtrListEnd == 0 && "End of list is not null?");
  *PtrListEnd = &Entry;
  PtrListEnd = Entry.second.setPrevInList(PtrListEnd);
  assert(*PtrListEnd == 0 && "End of list is not null?");
  addRef();               // Entry points to alias set...
}

/// mergeSetIn - Merge the specified alias set into this alias set.
///
void AliasSet::mergeSetIn(AliasSet &AS, AliasSetTracker &AST) {
  assert(!AS.Forward && "Alias set is already forwarding!");
  assert(!Forward && "This set is a forwarding set!!");

  // Update the alias and access types of this set...
  AccessTy |= AS.AccessTy;
  AliasTy  |= AS.AliasTy;
  Volatile |= AS.Volatile;

  if (AliasTy == MustAlias) {
    // Check that these two merged sets really are must aliases.  Since both
    // used to be must-alias sets, we can just check any pointer from each set
    // for aliasing.
    AliasAnalysis &AA = AST.getAliasAnalysis();
    PointerRec *L = getSomePointer();
    PointerRec *R = AS.getSomePointer();

    // If the pointers are not a must-alias pair, this set becomes a may alias.
    if (AA.alias(AliasAnalysis::Location(L->getValue(),
                                         L->getSize(),
                                         L->getTBAAInfo()),
                 AliasAnalysis::Location(R->getValue(),
                                         R->getSize(),
                                         R->getTBAAInfo()))
        != AliasAnalysis::MustAlias)
      AliasTy = MayAlias;
  }

  if (CallSites.empty()) {            // Merge call sites...
    if (!AS.CallSites.empty())
      std::swap(CallSites, AS.CallSites);
  } else if (!AS.CallSites.empty()) {
    CallSites.insert(CallSites.end(), AS.CallSites.begin(), AS.CallSites.end());
    AS.CallSites.clear();
  }

  AS.Forward = this;  // Forward across AS now...
  addRef();           // AS is now pointing to us...

  // Merge the list of constituent pointers...
  if (AS.PtrList) {
    *PtrListEnd = AS.PtrList;
    AS.PtrList->setPrevInList(PtrListEnd);
    PtrListEnd = AS.PtrListEnd;

    AS.PtrList = 0;
    AS.PtrListEnd = &AS.PtrList;
    assert(*AS.PtrListEnd == 0 && "End of list is not null?");
  }
}

void AliasSet::addPointer(AliasSetTracker &AST, PointerRec &Entry,
                          LocationSize Size, const AAMDNodes &AAInfo,
                          bool KnownMustAlias) {
  assert(!Entry.hasAliasSet() && "Entry already in set!");

  // Check to see if we have to downgrade to _may_ alias.
  if (isMustAlias() && !KnownMustAlias)
    if (PointerRec *P = getSomePointer()) {
      AliasAnalysis &AA = AST.getAliasAnalysis();
      AliasResult Result =
          AA.alias(MemoryLocation(P->getValue(), P->getSize(), P->getAAInfo()),
                   MemoryLocation(Entry.getValue(), Size, AAInfo));
      if (Result != MustAlias) {
        Alias = SetMayAlias;
        AST.TotalMayAliasSetSize += size();
      } else {
        // First entry of must alias must have maximum size!
        P->updateSizeAndAAInfo(Size, AAInfo);
      }
      assert(Result != NoAlias && "Cannot be part of must set!");
    }

  Entry.setAliasSet(this);
  Entry.updateSizeAndAAInfo(Size, AAInfo);

  // Add it to the end of the list...
  ++SetSize;
  assert(*PtrListEnd == nullptr && "End of list is not null?");
  *PtrListEnd = &Entry;
  PtrListEnd = Entry.setPrevInList(PtrListEnd);
  assert(*PtrListEnd == nullptr && "End of list is not null?");
  // Entry points to alias set.
  addRef();

  if (Alias == SetMayAlias)
    AST.TotalMayAliasSetSize++;
}